You rock - can't believe that you brought two new babies into the world at the same time. I've worked full-time with 3 kids the entire time, including at as a senior leader at a start-up. It can be done! My rule of thumb - there are glass balls and rubber balls in your life. Know which ones will bounce back if you let them drop and which won't
If a founder raised money without disclosing that they've already scheduled a sabbatical next year, I would expect them to get crucified for it. Now women might get worse deals unless there's some way they can signal to investors that they'll prioritize the startup above everything else.